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1.
《中国海洋工程》2021,(3)
The double-body heave wave energy converter(WEC) is one of the most conducive devices to absorb the wave energy from relative motion while the law of which is not well understood. This paper makes an in-depth study on this wave energy converter, by means of the combination of theoretical analysis and physical model experiment. The hydrodynamic characteristics and energy capture of the double-buoy under constant and linear Power Take-Off(PTO) damping are investigated. Influences of absolute mass and mass ratio are discussed in the theoretical model.Relative displacement amplitude and average power output are tested in the experiment to analyze the effect of the wave period and outer buoy's mass, while the capture width ratio(CWR) is also calculated. Results show that the wave period and mass of the buoys have a significant effect on the converter. Different forms of PTO damping have no influence on the optimal wave period and mass ratio of this device. It is recommended to select the double-buoy converter with a mass ratio of 0.80 and to place it in an area with the frequent wave period close to the natural period of the outer buoy to achieve the optimal energy capture. 相似文献
2.
本文对同轴双浮子波能发电装置进行了深入研究。采用Fortran语言对AQWA进行二次开发,并施以线性及非线性PTO反力,实现了装置的运动模拟,获得了双浮子装置的水动力特性及捕能情况。研究表明,波浪周期及内外浮子质量对装置获能影响显著,建议选用质量比为0.8的双浮子装置,并将其放置于周期与外浮子固有周期接近的海域中以实现最优捕能。 相似文献
3.
针对海工作业平台、海洋养殖网箱等海洋装备的安全防护问题，提出了一种带空气透平的后弯管浮式防波堤，该空气透平既可将作用在防波堤上的波浪能转化成机械能并用于发电，还可显著减小防波堤的锚链力。在介绍了防波堤原理和结构特点的基础上，设计了物理实验模型，并在实验室造波池内进行了模型试验，研究了波浪周期、波高、吃水深度与弯管数量等因素对后弯管浮式防波堤透射系数和锚链力的影响规律。研究结果表明，波浪周期越短，波高越低，防波堤的透射系数越小，锚
链力越小，其消波性能优于传统的浮式防波堤. 相似文献
4.
In recent years floating breakwaters are considered for creating calm basin under open sea conditions for short period of time. In this paper, experimental studies on the performance characteristics of a horizontal floating plate breakwater are presented. The results of this two-dimensional model study are for regular waves of shallow and intermediate water depths. Analysis of the results shows that the transmission coefficient is strongly influenced by wave steepness and relative length of breakwater. It is also found to be dependent, to a lesser extent, on the relative depth of draft. Mooring forces are found to increase with increasing wave steepness and relative depth of draft. The performance of this breakwater is compared with other types of breakwater reported by earlier workers. 相似文献
5.
浮式防波堤与振荡浮子式波浪能转换装置集成是一种较为合理的波浪能开发利用方式,基于方箱式浮式防波堤—波浪能转换集成系统和幕帘式防波堤的研究成果,提出了一种新型方箱—垂直挡浪板式浮式防波堤—波浪能转换集成系统,建立数学模型对该集成系统的水动力特性和能量输出特性进行研究。模型基于N-S方程,采用紧致插值曲线(CIP)方法结合浸没边界法(IBM)求解。运用数值模型探究在一定波浪条件下,动力输出系统(PTO)阻尼力的大小以及挡浪板对集成系统的水动力特性和能量转换特性的影响,得到如下结论:集成系统的俘获宽度比随PTO阻尼力的增大呈现先增大后减小的趋势,在阻尼力F_(PTO)=150 N时达到最大;相对于方箱型集成系统,增设0.1 m挡浪板后可使其最大俘获宽度比η_e提高33%左右;此外,集成系统的俘获宽度比随挡浪板长度增加而增大,增长趋势逐渐变缓,在挡浪板长度S_p=0.5 m时达到最大,此时俘获宽度比η_e=0.563 1。 相似文献
6.
LI Xue-yan WANG Qing YOU Zai-jin GUO Wei-jun ZHANG Jun-bin ZHAN Chao ZHANG Zhi-chen WANG Li-xue LI Qin 《中国海洋工程》2020,(1):89-98
Comprehensive experimental and numerical studies have been undertaken to investigate wave energy dissipation performance and main influencing factors of a lower arc-plate breakwater. The numerical model, which considers nonlinear interactions between waves and the arc-plate breakwater, has been constructed by using the velocity wave- generating method, the volume of fluid (VOF) method and the finite volume method. The results show that the relative width, relative height and relative submergence of the breakwater are three main influencing factors and have significant influence on wave energy dissipation of the lower arc-plate open breakwater. The transmission coefficient is found to decrease with the increasing relative width, and the minimum transmission coefficient is 0.15 when the relative width is 0.45. The reflection coefficient is found to vary slightly with the relative width, and the maximum reflection coefficient is 0.53 when the relative width is 0.45. The transmission and reflection coefficients are shown to increase with the relative wave height for approximately 85% of the experimental tests when the relative width is 0.19 0.45. The transmission coefficients at relative submergences of 0.04, 0.02 and 0 are clearly shown to be greater than those at relative submergences of 0.02 and 0.04, while the reflection coefficient exhibits the opposite relationship. After the wave interacts with the lower arc-plate breakwater, the wave energy is mainly converted into transmission, reflection and dissipation energies. The wave attenuation performance is clearly weakened for waves with greater heights and longer periods. 相似文献
7.
针对波浪能转换装置(WEC)研究重点主要集中在能量捕获效率方面,而忽略其附带的消波功能的问题。基于Open FOAM程序,建立垂荡浮子式波浪能发电装置与桩式约束的浮式防波堤的集成系统(OBC-FB)。主要研究WEC中的重要组件动力输出系统(PTO)对集成系统波能捕获效率及消波性能的影响。分析流体黏性影响下线性PTO系统的最优PTO阻尼特性。开发非线性电磁阻尼模型与线性PTO系统性能进行比较。结果显示,考虑黏性影响下线性的最优PTO阻尼系数略大于无黏的理论值;适当增大PTO阻尼系数可以获得更大的波能捕获宽度比(CWR),从而可以保证装置单位特征尺寸的波能转换效率更高,同时可以在更宽波况范围保证消波性能;相较于线性PTO阻尼系统,非线性电磁PTO阻尼系统可以更好地兼顾波能捕获效率和消波性能。因此,在OBC-FB集成系统的优化设计中,PTO阻尼系统是一个重要的优化参数。 相似文献
8.
弧板式透空堤消浪性能影响因素数值研究 总被引：1，自引：0，他引：1
弧板式透空堤是由弧型板组成的新型防波堤结构。为探讨其透射系数的影响因素,利用Fluent软件基于N-S方程构建了波浪与板式透空堤相互作用的数值模型,讨论了相对潜深、入射波周期、相对波高、相对板宽和结构型式对透射系数的影响。结果表明:弧板式透空堤的透射系数随着相对波高和入射波周期的增大而增大,在静水面附近透射系数最小,尤以静水面和略高于静水面时的消浪效果最佳;在相同波浪要素条件下,静水面及其上0.02 m和0.04 m位置处,弧板式透空堤的消浪效果明显优于平板式透空堤。 相似文献
9.
波浪作用下方箱-水平板浮式防波堤时域水动力分析 总被引：1，自引：0，他引：1
在线性化势流理论范围内求解方箱-水平板浮式防波堤的波浪绕射和辐射问题,从时域角度分析了浮式防波堤的水动力特性.采用格林函数法将速度势定解问题的控制微分方程变换成边界上的积分方程进行数值求解,浮式防波堤的运动方程采用四阶Runge-Kutta方法求解.对不同层数水平板的浮式防波堤的波浪透射系数、运动响应和锚链受力进行了计算分析,结果表明方箱相对宽度对方箱-水平板浮式防波堤的波浪透射作用有重要的影响,透射系数随着方箱相对宽度的增加而减小.对于方箱加二层水平板的浮式防波堤,在本研究的计算条件下,当方箱相对宽度从0.110增加至0.295时,透射系数从0.88减小至0.30.水平板有利于增加浮式防波堤对波浪的衰减作用,但随着水平板层数从0增加至2,这种波浪衰减作用增加的程度趋弱.方箱-水平板的浮式防波堤的运动量小于单一方箱防波堤的运动量.与此对应,方箱-水平板防波堤的锚链受力小于单一方箱防波堤的锚链受力. 相似文献
10.
Based on a two-dimensional linear water wave theory, this study develops the boundary element method (BEM) to examine normally incident wave scattering by a fixed, submerged, horizontal, impermeable plate and a submerged permeable breakwater in water of finite depth. Numerical results for the transmission coefficients are also presented. In addition, the numerical technique's accuracy is demonstrated by comparing the numerical results with previously published numerical and experimental ones. According to that comparison, the transmission coefficient relies not only on the submergence of the horizontal impermeable plate and the height of the permeable breakwater, but also on the distance between horizontal plate and permeable breakwater. Results presented herein confirm that the transmission coefficient is minimum for the distance approximately equal to four times the water depth. 相似文献
11.
波浪与起伏水平板防波堤相互作用数值模拟 总被引：1，自引：1，他引：0
利用自主研发的基于紧致插值曲线CIP(constrained interpolation profile)方法的数学模型,开展规则波与起伏水平板防波堤相互作用的数值模拟研究。模型在笛卡尔直角坐标下建立,以CIP方法为流场基本求解器,分步求解Navier-Stokes方程,利用高精度的流体体积类型的THINC/SW (tangent of hyperbola for interface capturing with slope weighting)方法重构自由液面,采用浸入边界IBM(immersed boundary method)方法处理波浪与起伏板防波堤的耦合作用问题,通过动量源项造波方法模拟波浪的产生。重点关注波浪的浅水变形和板两端涡旋脱落的非线性现象,分析不同潜深、波要素下的板周围流场分布、板的运动响应和波浪的反透射系数。结果表明:起伏水平板主要通过能量反射、板上浅水变形和板两端的涡脱落消能,能有效减小板后波高,具有作为防波堤的可行性。 相似文献
12.
The present study proposed a floating multi-body wave energy converter composed of a floating central platform, multiple oscillating bodies and multiple actuating arms. The relative motions between the oscillating bodies and the floating central platform capture multi-point wave energy simultaneously. The converter was simplified as a forced vibration system with three degrees of freedom, namely two heave motions and one rotational motion. The expressions of the amplitude-frequency response and the wave energy capture width were deduced from the motion equations of the converter. Based on the built mathematical model, the effects of the PTO damping coefficient, the PTO elastic coefficient, the connection length between the oscillating body and central platform, and the total number of oscillating bodies on the performance of the wave energy converter were investigated. Numerical results indicate that the dynamical properties and the energy conversion efficiency are related not only to the incident wave circle frequency but also to the converter's physical parameters and interior PTO coefficients. By adjusting the connection length, higher wave energy absorption efficiencies can be obtained. More oscillating bodies installed result in more stable floating central platform and higher wave energy conversion efficiency. 相似文献
13.
鉴于双弧板式透空堤的消浪性能仍不理想,提出了一种潜堤—双弧板组合结构,并基于OpenFOAM软件建立了波浪与该结构相互作用的数值模型,采用试验结果对所建数值模型进行验证。在此基础上,讨论了该新型结构的消浪特性、波压力分布特征以及所受波浪力的影响因素。结果表明,透射系数随相对板宽的增大而减小,反射系数则相反。透射与反射系数随相对潜深的变化较为显著。当结构位于静水位上方（即相对潜深为-0.05）时,透射系数最小而反射系数最大;当结构位于静水位下方（即相对潜深为0.05）时,透射系数最大而反射系数最小。该组合结构两块弧板上下表面的正负压力变化关于横轴近似对称,不同测点处的压力值差异显著。水平波浪力与垂直波浪力的变化趋势大致相似,但垂直波浪力远大于水平波浪力。研究结果可为其工程应用提供理论指导与技术支撑。 相似文献
14.
Experimental investigation of the harmonic generation by waves over a submerged plate 总被引：1，自引：0，他引：1
Experiments in a wave flume have been performed to analyse the nonlinear interaction between regular gravity waves and a submerged horizontal plate used as breakwater. A new method, based on the Doppler shift generated by a moving probes, has been used to discriminate the incident fundamental mode and the reflected fundamental mode. The relationships of the reflection and transmission coefficients to the wave number at different submergence depth ratios are presented. The accurate discrimination, by this method, of the phase-locked and free modes allows the quantification of the higher harmonics generated by the breakwater and the analysis of the nonlinear interaction between the waves and the submerged plate. The transfer of energy from the fundamental mode to higher harmonics is very large in the cases of small submergence depth ratios. The vortices produced at the edges take part in the production of higher harmonics by interaction with the free surface but involve, at the same time, a dissipation process that increases the efficiency of the breakwater. 相似文献
15.
《Ocean Engineering》1999,26(4):325-341
Based on a two-dimensional linear water wave theory, this study develops the boundary element method (BEM) to examine normally incident wave scattering by a fixed, submerged, horizontal, impermeable plate and a submerged permeable breakwater in water of finite depth. Numerical results for the transmission coefficients are also presented. In addition, the numerical technique's accuracy is demonstrated by comparing the numerical results with previously published numerical and experimental ones. According to that comparison, the transmission coefficient relies not only on the submergence of the horizontal impermeable plate and the height of the permeable breakwater, but also on the distance between horizontal plate and permeable breakwater. Results presented herein confirm that the transmission coefficient is minimum for the distance approximately equal to four times the water depth. 相似文献
16.
柔性水囊潜堤由橡胶制成，内部充水，具有结构简单、造价低廉等优点，能较好满足人工岛、跨海桥梁、海洋平台等基础设施建设工程对简单便携、拆装方便的临时防波堤的需求。为了探究柔性水囊潜堤的消波特性，在溃坝水槽内开展溃坝波与半圆柱形柔性水囊潜堤相互作用的试验研究，重点探究柔性水囊潜堤与溃坝波相互作用过程中水位变化特性，并与半圆柱刚性潜堤的性能进行比较；同时分析柔性水囊潜堤内部初始水压和浸没深度等参数对其消波性能的影响。结果表明：柔性水囊潜堤能够用作临时防波堤来衰减波浪；与半圆柱刚性潜堤相比，柔性水囊潜堤在降低溃坝波无量纲最大水位、提高消波性能方面更具优势；内部初始水压是影响柔性水囊潜堤消波性能的重要因素，适当降低内部初始水压，有利于增强柔性潜堤的变形程度，进而增加波能耗散，可获得更好的消波效果；而增加浸没深度即潜深，会使得柔性水囊潜堤对溃坝波的影响程度降低，消波效果减弱。 相似文献
17.
The wave transmission characteristics and wave induced pressures on twin plate breakwater are investigated experimentally in regular and random waves.A total of twenty pressure transducers are fixed on four surfaces of twin plate to measure the wave induced dynamic pressures.The spatial distribution of dynamic wave pressure is given along the surface of the twin plate.The uplift wave force obtained by integrating the hydrodynamic pressure along the structure is presented.Discussed are the influence of different incident wave parameters including the relative plate width B /L,relative wave height /i H a and relative submergence depth s /a on the non-dimensional dynamic wave pressures and total wave forces.From the investigation,it is found that the optimum transmission coefficient,t K occurs around B /L 0.41 ~ 0.43,and the twin plate breakwater is more effective in different water depths.The maximum of pressure ratio decreases from 1.8 to 1.1 when the relative submergence depth of top plate is increased from 0.8to +0.8. 相似文献
18.
19.
Lao Guosheng Feng Hong Associate Professor Dalian University of Technology Dalian Postgraduate Dalian University of Technology Dalian 《中国海洋工程》1992,(4)
- In this paper, the theoretical calculation of floating breakwater performance in regular waves with arbitrary wave direction is discussed. Under the hypothesis of linearized system and applying the strip theory, we can solve the boundary condition problems of diffraction potential and radiation potential. Introducing the asymptotic expression of the wave velocity potential at infinity and using wave energy conservation, we can separately calculate the transmitted waves generated by the sway, heave and roll motion of the floating breakwater and by the fixed breakwater. Finally, we define the amplitude ratio of the transmitted wave to the incident wave as the transmitted wave coefficient CT which describes the floating breakwater effectiveness. Two examples are given and the theoretical results obtained by the present method agree well with experimental results. 相似文献
20.
The wave transmission, reflection and energy dissipation characteristics of ‘’-type breakwaters were studied using physical models. Regular and random waves in a wide range of wave heights and periods and a constant water depth were used. Five different depths of immersion (two emerged, one surface flushing and two submerged conditions) of this breakwater were selected. The coefficient of transmission, Kt, and coefficient of reflection, Kr, were obtained from the measurements, and the coefficient of energy loss, Kl was calculated using the law of balance of energy. It was found that the wave transmission is significantly reduced with increased relative water depth, d/L, whether the vertical barrier of the breakwater is surface piercing or submerged, where ‘d’ is the water depth and ‘L’ is the wave length. The wave reflection decreases and energy loss increases with increased wave steepness, especially when the top tip of the vertical barrier of this breakwater is kept at still water level (SWL). For any incident wave climate (moderate or storm waves), the wave transmission consistently decreases and the reflection increases with increased relative depth of immersion, Δ/d from −0.142 to 0.142. Kt values less than 0.3 can be easily obtained for the case of Δ/d=+0.071 and 0.142, where Δ is the height of exposure (+ve) or depth of immersion (−ve) of the top tip of the vertical barrier. This breakwater is capable of dissipating wave energy to an extent of 50–80%. The overall performance of this breakwater was found to be better in the random wave fields than in the regular waves. A comparison of the hydrodynamic performance of ‘’-type and ‘T’-type shows that ‘T’-type breakwater is better than ‘’-type by about 20–30% under identical conditions. 相似文献